The ability to detect and quantify low-abundance biomolecules, including antigens, antibodies, receptors, ligands and nucleic acids, in ultra-small volumes of complex biological matrices, including samples from single cells, is critical to many disciplines, such as medical diagnostics, environmental monitoring and chemical analysis. To address this challenge, efficient concentration and separation techniques are critically needed.
Typical methods for detecting biomolecules utilize specific binding between a target biomolecule and a corresponding binding partner to form a readily detectable complex. Many electrochemical and colorimetric approaches rely on equilibrium-based assays. However, these assays can take hours or more often days of waiting to reach equilibrium which significantly slows down throughput. The detection and capture moieties, such as ssDNA probes or antibodies, may have relatively high dissociation constants restricting the limit of detection to concentrations above the desired range, and resulting in poor sensitivity. Dissociation constants between intended and non-intended binding partners are usually very similar and thus lead to poor selectivity and false positive signals in many of the current assays.
Accordingly, there is a need in the art for methods that improve the sensitivity, speed and simplicity of biomolecule detection, and especially for those that are readily adaptable for detecting a wide variety of biomolecules.